1. Field of the Invention
The present invention relates to a packaging tray to be used when packing fruit or other easily bruised objects of slightly varying size in several layers in a box so that the packaging tray of an upper layer rests on the fruit of the layer below, and the material used for the structure is fiber pulp or plastic in a substantially single layer.
Such a packaging tray for fruit has almost calotte-shaped depressions for fruit, and these depressions are placed in rows, each row having several depressions. The number of depressions depends on their size and thereby on the size of the fruit to be packed.
When packing fruit, two kinds of packaging trays are used alternately in different layers to the effect that a fruit of a lower layer always coincides with an intermediate space between the fruit of the upper layer.
2. Description of the Prior Art
Generally used is a packaging tray for fruit which rests on the fruit of a lower layer so that each fruit is touched by the lower surfaces of the closest fruit depressions of the upper packaging tray, that is, the fruit is wedged between the depressions. Such wedging would not be so damaging if the fruit were of equal size and preferably spherical, in which case there would be a great number of contact points. In practice, however, owing to the non-spherical and varying shape of fruit, there are few contact points and these receive excessive surface pressure.
In order to eliminate the problems due to the non-spherical shape of fruit, a structure is used in which there is a plane surface in the area between the fruit depressions and at such a height that its lower surface rests against the highest point of a fruit of the lower level. Such a solution is described in U.S. Pat. No. 3,040,923.
Also known is a construction in which there is a slightly downward concave supporting surface in the supporting area between two depressions, and this supporting surface is at such a height that it rests against the highest point of the fruit of the lower level and allows for a slightly non-spherical shape. Such a downward concave supporting surface may also be partial, as suggested in U.S. Pat. No. 3,28l,003.
Previously known packaging trays for fruit do not yield sufficiently and therefore, when used, rest on a few large fruit, thereby bruising their sensitive surface.